DESCRIPTION (Applicant's Abstract): The strikingly high rate of comorbid post-traumatic stress disorder (PTSD) and substance use disorders (SUDs) necessitates further understanding of how basic mechanisms underlying PTSD influence aspects of SUDs and vice versa. Conceptualized as a product of conditioning, crime- and substance-related cues have been identified as having important functions in the development and maintenance of each disorder. However, researchers have not yet studied these cues in individuals who suffer from both PTSD and SUD. The overall study design involves the measurement of cue reactivity by evaluating 1) subjective ratings of affect and alcohol/drug craving and 2) physiological responses to alcohol/drug and crime-related cues. One principal hypothesis is that individuals with both PTSD and SUD will demonstrate higher levels of drug craving in response to crime-related cues than individuals in the following three groups: SUD only, PTSD only, and "no disorder." A second hypothesis is that individuals with comorbid PTSD and SUD, as compared to individuals in the other three groups, will have a stronger negative affective response to crime-related cues, which, in turn, creates a negative affective state that will lead to higher drug craving in response to drug cues. Comprehensive assessment will be conducted to determine Axis 1 disorders, complete history of trauma, and severity of SUD. Following completion of interview and self-report questionnaires, each eligible subject will view standardized slides in each of five categories: substance, crime, neutral, unpleasant, and pleasant. Physiological measures (heart rate, electrodermal activity, orbicularis, corrugator and zygomatic EMG) will be utilized to measure cue reactivity. Subjective ratings of affect and drug craving will be obtained for each picture during a second presentation of the slides. In Part 2, subjects will undergo an imagery task, wherein they are exposed to a script (auditory) constructed from their subjectively rated "worst" crime event. This exposure will be followed by exposure to drug cues, followed by ratings of affect and craving. Measures of physiological arousal will occur throughout the experiment. The results of this investigation may be critical for developing treatment interventions designed to address the needs of the patients with a SUD and comorbid PTSD. More accurate identification of the types of cues that are capable of triggering drug craving and subsequent drug use will aid the development of interventions to extinguish such connections, and therefore, lead to more effective methods of treating both PTSD and SUD.